Local and international media groups have condemned the verdict against Sayed Perwiz Kambakhsh, which family members say followed a "secret trial" at which Kambakhsh had no legal counsel.
The Institute for War and Peace Reporting (IWPR), a nongovernmental group that helps train journalists in troubled spots, has meanwhile accused the authorities of prosecuting Kambakhsh in order to punish his brother, a contributor to IWPR publications.
Family members denounced the verdict, saying the January 22 trial in Mazar-e Sharif was held behind closed doors and they did not even know the hearing had been scheduled.
Kambakhsh's brother, Sayed Yaqub Ibrahimi, tells RFE/RL's Radio Free Afghanistan that the verdict was "unjust" and his brother did not have a lawyer defending him at the hearing.
"I told [my brother], 'Don't worry about this. It is not the final decision of the Afghan courts,'" Ibrahimi says. "But, anyway, every member of our family is concerned about it. We are sorry to see this unjust decision by the Balkh court."
Sayed Perwiz Kambakhsh, a journalism student at Balk University who also worked for the newspaper "Jahan-e Naw" (The New World), was arrested in late October over a controversial article that commented on verses in the Koran that were about women.
Kambakhsh's brother and other sources said the article had in fact been taken off the Internet and Kambakhsh had simply distributed copies of it among fellow university students.
"We feel very strongly that this is a complete fabrication on the part of the authorities up in Mazar, designed to put pressure on Parwez's brother Yaqub, who has done some of the hardest-hitting pieces outlining abuses by some very powerful commanders in Balkh and the other northern provinces," IWPR country manager Jean MacKenzie says.
MacKenzie notes that authorities in Balkh had searched Ibrahimi's computer and taken contact details of sources, adding that "we feel that what is happening with Parwez is not a very veiled threat against Yaqub Ibrahimi."
Reporters Without Borders, a Paris-based media watchdog, says it was "shocked" at the verdict against Kambakhsh and has urged Afghan President Hamid Karzai to intervene.
Afghan media outlets have sprung up in large numbers since the ouster of the hard-line Taliban regime in late 2001, although press freedoms frequently run up against official obstacles or opposition from conservative forces that include the clergy.
A three-judge panel concluded on January 22 that the article in question violated the tenets of Islam.
Rahimullah Samandar, who heads Afghanistan's Independent Journalist Association, strongly condemned the verdict against Kambakhsh. He tells Radio Free Afghanistan that the ruling contravenes the country's 2004 constitution.
"The Afghan Independent Journalists Association, and the...the Committee to Protect Afghan Journalists..., both organizations, strongly condemn this decree," Samandar says. "This is illegal, this is unjust, it's unfair. It is in accordance with neither Afghan law nor the Afghan Constitution."
The constitution, adopted after the ouster of the Taliban, described freedom of expression as "inviolable" within the law, and committed authorities to respecting the Universal Declaration of Human Rights. But it also stipulates that "no law can be contrary to the beliefs and provisions of the sacred religion of Islam."
Samandar also says President Karzai should reverse the verdict, which he says was made under the pressure of Islamic clerics.
"This was completely a decree [made] under pressure, under religious pressure, under political pressure, and we are against this, and we don't accept this," Samandar says. "We will appeal to other courts. We will appeal to the international community, to international media organizations, and also to the Afghan president, and the Afghan parliament to help us."
Reporters Without Borders has urged Karzai to intervene in the Kambakhsh case "before it is too late."
"We are deeply shocked by this trial, carried out in haste and without any concern for the law or for free expression, which is protected by the [Afghan] constitution," the group said in a statement on January 22.
In an interview with Radio Free Afghanistan, Balkh Province Attorney-General Hafizullah Khaliqyar defends the sentence, adding that the trial was conducted in a "very Islamic way."
"This was not a violation of human rights or press freedom, not a violation of rights of a journalist," Khaliqyar says. "[Kambakhsh] violated the values of Islam. He did not make a journalistic mistake; he insulted our religion. He misinterpreted the verses of the Koran and distributed this paper to others. All ulama [Islamic clerics] have condemned his act."
Clerics had been pushing for Kambakhsh to be punished. They reportedly organized a demonstration in Mazar-e Sharif last week against the journalist, demanding that the government not release him.
Clerics have also claimed that Kambakhsh confessed to having humiliated Islam.
But Abdullah Attaei, an expert in Shari'a law who studied at Al-Azhar University in Egypt, tells Radio Free Afghanistan that the verdict does not appear to be in line with Islamic law.
"If the convicted person doesn't accept that he wrote the article, and if he denies being quoted, then no court can judge his faith [according to Shari'a law]," Attaei says. "When he denies that he wrote the article, then no one has the right to arrest or investigate him or even to try to prove him guilty."
Journalists who defended Kambakhsh came under attack from authorities on January 21. Provincial Attorney-General Khalikyar vowed at a media briefing that he would arrest any journalist who defended Kambakhsh.
The case will now go to the first of two appeals, with Kambakhsh in custody throughout the appeal procedure.
A chief judge from Balkh Province, Fazel Wahab, said only President Karzai can forgive Kambakhsh because the journalist has confessed to the crime.
Central authorities have struggled for decades to reconcile efforts to liberalize Afghanistan's media environment with counterefforts by reactionary elements that frequently cite adherence to religious teachings. A major experiment in independent media began with King Mohammad Zaher's 1964 constitution, which ushered in what is frequently referred to as the "decade of democracy," although the Soviet puppet and subsequent hard-line governments fought hard to reverse its legacy in most respects.
Karzai issued a decree setting out a new law on mass media in December 2005 -- just days before the inauguration of the country's first directly elected legislature -- but frequent disputes have arisen on how the law should be interpreted and enforced.
(RFE/RL's Radio Free Afghanistan contributed to this report.)